Wada Y, Ishiguro K, Itoh T J, Uchida T, Hotani H, Saito T, Kishimoto T, Hisanaga S
Laboratory of Cell and Developmental Biology, Faculty of Biosciences, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan.
J Biochem. 1998 Oct;124(4):738-46. doi: 10.1093/oxfordjournals.jbchem.a022174.
Phosphorylation of tau, a heat-stable neuron-specific microtubule-associated protein, by cdk5 was stimulated in the presence of microtubules (MTs). This stimulation was due to an increased phosphorylation rate and there was no increase in total amount of phosphorylation. Two-dimensional phosphopeptide map analysis showed that MTs stimulated phosphorylation of a specific peptide. Using Western blotting with antibodies that the recognized phosphorylation-dependent epitopes within tau, the phosphorylation sites stimulated by the presence of MTs were found to be Ser202 and Thr205 (numbered according to the human tau isoform containing 441 residues). MT-dependent phosphorylation at Thr205 was observed in situ in rat cerebrum primary cultured neurons. Stimulated phosphorylation at Ser202 and Thr205 decreased the MT-nucleation activity of tau, which is in contrast to MT-independent phosphorylation at Ser235 and Ser404.
在微管（MTs）存在的情况下，细胞周期蛋白依赖性激酶5（cdk5）对tau（一种热稳定的神经元特异性微管相关蛋白）的磷酸化作用增强。这种增强是由于磷酸化速率增加，而磷酸化总量并未增加。二维磷酸肽图谱分析表明，微管刺激了特定肽段的磷酸化。使用针对tau中识别磷酸化依赖性表位的抗体进行蛋白质印迹分析，发现微管存在时刺激的磷酸化位点为Ser202和Thr205（根据含441个残基的人tau异构体编号）。在大鼠大脑原代培养神经元中观察到Thr205处的微管依赖性磷酸化。Ser202和Thr205处受刺激的磷酸化降低了tau的微管成核活性，这与Ser235和Ser404处的非微管依赖性磷酸化相反。
